U.S. Representative John Culberson, Chairman of the House Appropriations Subcommittee on Commerce, Justice, and Science, speaks to employees at Oceaneering Space Systems, Monday, April 30, 2018, in Houston. ( Mark Mulligan / Houston Chronicle )

Photo: Mark Mulligan, Houston Chronicle / Houston Chronicle

WASHINGTON — Texas Democrats targeting Republican Congressman John Culberson in Houston are challenging nearly $50,000 in campaign spending since 2004 on books, coins, Civil War memorabilia and other collectibles, some reported as “donor gifts.”

Draft copies of complaints to the Federal Election Commission and the independent Office of Congressional Ethics question the expenses in light of Culberson’s personal interest in military history.

Culberson has reported selling as much as $1.3 million in antiques and collectibles since 2010, something he says he does as a hobby. Because he considers his collection a personal rather than an investment asset, he has not been required to publicly detail his purchases or holdings in congressional disclosure reports.

Culberson’s campaign said Monday said that all of the spending in question was either for research material or modest gifts to campaign contributors and volunteers over the 19 years he’s been in office.

His campaign dismissed the allegations as an “obvious partisan attack.”

The complaints, drafted in the name of Houston Democratic activist Daniel Cohen, a resident of Culberson’s 7th Congressional District, seek investigations into whether the congressman used campaign funds to build his personal collection, something Culberson denies.

“There are questions about whether he’s using his campaign funds as a bank,” Cohen said. “That’s a classic thing people are tired of.”

Cohen said the allegations were brought to him by state Democratic party officials in Texas, based on research compiled by the Democratic Congressional Campaign Committee, the political arm of the House Democrats.

Nevertheless, Cohen said he is bringing the complaints forward as a private citizen. “I’m filing as a constituent,” he said.

Officials from the Texas Democratic Party did not respond to requests for comment about the timing of the complaints, which were submitted to the two agencies on Wednesday.

Either way, analysts say their complaints are unlikely to be resolved before the Nov. 6 election in which Culberson faces a forceful challenge from Democrat Lizzie Pannill Fletcher, a Houston attorney.

Culberson spokeswoman Catherine Kelly questioned the motives and the timing of the leaked complaints, coming several days before Culberson and Fletcher meet with the newspaper’s editorial board.

“The documents drafted by Texas Democrats against Congressman Culberson are an obvious partisan attack and ripped directly from the DCCC, are purely speculative, without merit, and have been curiously leaked to the Houston Chronicle fewer than three days before a joint appearance between the Congressman and his opponent,” she said.

Democrats consider the 7th District, which was narrowly won by Hillary Clinton in the 2016 presidential election, as one of their best pickup opportunities in the midterm elections as they seek to win control of the U.S. House.

The allegations follow recent Democratic attacks surrounding Culberson’s investment in an obscure Australian biotech stock at the center of insider trading charges filed against New York Republican Chris Collins earlier this month. Culberson was one of a half-dozen lawmakers who bought into the company at around the same time in early 2017. He eventually sold at a loss before the company’s share price plummeted to pennies on the dollar.

Culberson said he learned about the bio-tech company, Innate Immunotherapeutics, on his own.

The new complaint also comes several weeks after California Republican Duncan Hunter was indicted on charges of using $250,000 in campaign contributions, some booked as “donor gifts,” for personal use.

Research materials helped Culberson study climate change, aides say

Democrats have made no specific allegations or provided evidence of any criminal conduct by Culberson. Instead, they have questioned the legitimacy of his campaign’s frequent purchases on Amazon.com, Borders and Barnes & Noble.

In all, they document $32,981 in expenses reported as “books” and “research materials” since 2009, as well as $17,000 on gifts, including antiques and military collectibles, since 2004. More than $5,000 was spent on Civil War memorabilia since 2010.

The complaints also spotlight the use of campaign funds in 2009 to pay for a $375 membership in the Texas State Rifle Association, and in 2012 for a $309 purchase at the Black Hills Institute, which sells and rents fossils.

“It is very unlikely that a congressional campaign committee needs to buy or rent fossils to win a federal election,” the Democrats wrote in their complaint.

Culberson’s aides explained the purchase as research material on paleo-climatology, a subject that would help him understand climate science for his position on an appropriations subcommittee that oversees the National Oceanic and Atmospheric Administration. They said the materials helped give him a better understanding of the changing levels of carbon dioxide in the atmosphere.

Culberson has sometimes questioned the scientific consensus on man-made climate change, though he says his mind remains open to new information.

His campaign justified paying for his membership in the NRA-affiliated Texas State Rifle Association as a political expense. He is not a gun collector.

Aides describe Culberson as an avid reader and student of history and science, adding that many of the books he bought through his campaign pertained to his committee assignments in Congress.

His campaign does not dispute the spending on donor gifts, but noted that the $17,000 total works out to an average of less than $1,000 for each year he’s been in Congress.

Culberson’s accounting of his military collectibles has been questioned before because while he reports the income he earns from their sales, he lists their value as zero while they are in his personal collection.

Some ethics analysts have questioned the lack of transparency in the transactions.

“There are plausibility problems to argue you didn’t buy these for investments, but you sold them for more than a million dollars,” said Fred Wertheimer, president and CEO of Democracy 21, a nonpartisan government watchdog group. “We don’t know what he paid, or the value of collection. Those are the questions that come up here.”

Culberson has said he is following the direction of the House Ethics Committee, which does not regard his collectibles as reportable assets until he sells them.

Kevin Diaz came to the Houston Chronicle in February 2014 with more than a decade of experience covering Washington. Before that, he was the chief Washington correspondent for the Minneapolis Star Tribune, where he got his start in journalism in 1984 as a night cops reporter. During his tenure in Minneapolis, he won awards for his coverage of gang crime and city hall. He also taught public affairs reporting at the University of Minnesota, where he received his Master’s. After a stint at the Washington (D.C.) City Paper, Kevin went back to the Star Tribune, where he won national awards for articles on globalization and immigration. He also covered the 9/11 terrorist attacks from Washington and New York. Born and raised in Italy, Kevin has reported from Italy, Brazil, Mexico, and Cuba, where he covered Jesse Ventura’s 2002 trade mission. In 2003, he filed daily Iraq War dispatches for McClatchy Newspapers from the U.S. Central Command in Qatar. In 2006, he covered the presidential election standoff in Mexico. He also has covered Washington for the Anchorage Daily News and the Idaho Statesman.